The present invention relates to a ceramic disc cartridge for mixing fluids in faucets and the like.
As is known, fluid mixing faucets conventionally comprise ceramic disc cartridges which, in their basic concept, can be classified into three types and, more specifically, a first direct movement type, a second indirect movement type and a third ball-movement type.
In the direct movement cartridges, the movable plate is coupled to a driving rod which drives said movable plate with an opening and closing movement (either frontward or inward), the rotary movement being provided by an element thereon the rod is pivoted by suitable pivoting means.
More specifically, this rotary movement is provided by a specifically designed rod, including, for example, parallel planes, fork end portions, or rack end portions, and so on.
Under the effect of the combination of two distinct and separate movements, the movable plates, at any positions thereof between the maximum closure and maximum opening positions thereof, will always perform a full maximum rotary movement, from a hot to a cold position, being delimited by suitable detent means.
In the indirect movement cartridges, which movement is also called an idling or hunting movement, as shown in FIG. 1, the collar 1 supports a rod 2 through a pin 3 operating as a pivot pin for the driving rod 2.
The collar 1 is engaged within a cover 4.
The rotary movement of the collar 1, engaged in the cover 4, is delimited by detent elements 5, provided on the flange 6 of the collar, said detent elements engaging with counter-detent elements 7 formed on the cover.
The ball-shaped end portion 8 of the rod 2 is provided for engaging in a corresponding recess, defined by the coupling body 10, which is provided with a lug 11 having a rounded configuration provided for engaging in a guide 12.
The latter is defined by the cover 4 between the counter-detent elements 7.
With the cartridge in its closed condition, the ball 8 of the rod 2 and related recess of the coupling body 10 are coaxial with respect to the hole 13 defined by the cover 2 and are also coaxial with respect to the cylindric body 14 of the collar 1.
By turning the cartridge rod on itself, for performing the mixing movement, while it is in its closing position, the ball 8 will turn in its recess without causing any movements of the coupling body 10.
The coupling body 10, in particular, is coupled to the movable ceramic plate 15 of the cartridge.
As the driving rod is displaced from the full closure position to the opening position thereof, which can be either a partial or a full opening position, and is turned in the mixing direction, the lever arm, formed between the ball position and the axis of the hole 13 of the cover 4, will allow the coupling body 10 connected to the movable plate 15 to be displaced.
This displacement of said body 10 will increase as the lever arm provided by the opening of said rod is increased.
The resultant displacement, which is also called a "hunting" type of displacement, is a characteristic movement and it is generated by a combination of a rotary movement of the casing in the recess in which the ball 8 is engaged, with respect to the hole 13, and the sliding movement of the lug 11 in the guide 12 of the cover 4.
The sliding of the guide lug constitutes a constraint and, accordingly, it subtracts a freedom degree from the system.
This type of movement can be considered like to the rod movement of a rod-crank mechanism, and the coupling body 10 can be compared to the rod having an end portion thereof coupled to a piston (the lug 11 sliding in the guide 12) and the other end thereof coupled to the crankshaft formed by the casing in which the ball 8 is engaged.
In this mechanism, the crank radius corresponds to the opening displacement of the ball, with respect to the rotary center, i.e. the hole 13 of the cover, and, accordingly, it can be continuously varied from 0, with the rod in a vertical condition and the cartridge in a closed condition, to a maximum value, i.e. with the rod in a slanted condition and the cartridge in a full opened condition.
The third known type, as stated, is a so-called ball or spherical displacement, in which the rod can be driven or displaced with a "cloche" type of movement, through a ball type of articulation.
This movement is performed by a direct movement plate and, accordingly, with the rod which cannot turn about its vertical axis, with respect to the plate, or with the rod provided with a ball end portion, but by limiting the possible displacement of the movable plate.
In the second case, due to the lacking of a constraint, the plate can turn with respect to the axis of the ball thereon it is pivoted.
Accordingly, its configuration can be exclusively a circular configuration, with the center thereof arranged in the seat or recess for the ball: the hollow providing the communication between the inlet and the outlet can also be exclusively of circular configuration and concentrically arranged with respect to the ball.